Interpol has now been informed about the disappearance of Patrick Skillen.
Mr.Skillen was last seen in Buncrana over two weeks ago.
He has been living in Buncranna since 2009.
Both the PSNI and An Garda Siochana are still concerned about the whereabouts of 61 year old Patrick Skillen.
Patrick has been described as having blue eyes and a shaved head.
He is 5 feet 8 inches tall, has a round face and speaks with a Belfast accent.
He was last seen leaving his flat on CCTV Camera in Buncrana Co. Donegal on Monday, September 14th at 7.17 am.
Anyone with information in relation to Patrick's whereabouts or have any information are asked to contact the Gardaí at Buncrana on 0749361555, the Garda Confidential Telephone Line 1800 666 111 or any Garda Station.